Process of manufacturing semiconductor wafers to produce integrated circuit (IC) chips involves a number of steps, such as lithography, deposition and etching, etc. Due to complexity of the manufacturing process, some IC chips will inevitably possess defects. Therefore, the defective IC chips are tested before wafer dicing is performed to separate above mentioned IC chips from the semiconductor wafers, so as to determine whether the IC chips are defective.
Please refer to FIG. 1. FIG. 1 is a diagram illustrating a conventional probing device 10. The conventional probing device 10 comprises a cage 11, a printed circuit board (PCB) 12, a space transformer 14 and a probe head 16. The space transformer 14 is disposed on the PCB 12 via a plurality of solders 18, and the probe head 16 is fixed by the cage 11. Further, the probe head 16 comprises a plurality of probes 162. One end of the probe 162 is in contact with a pad 141 disposed on the space transformer 14, and the other end of the probe 162 is in contact with a chip (not illustrated) on the wafer being tested, so the chips (not illustrated) on the wafer can be tested via the probes 162. Circuitries (not illustrated) are disposed in the space transformer 14, so that the probes 162 on the probe head 16 can be electrically connected to the PCB 12 via these circuitries. In this way, testing signals received by the probes 162 can be transferred to the PCB 12 via the space transformer 14, for further follow-up analysis.
In the current market, the probing device 10 is produced and assembled by dedicated probing device manufacturers. The space transformer 14, however, is usually provided by IC manufacturers or IC design companies, due to cost issue. On the other hand, only one probe head 16 is disposed on the space transformer 14 shown in FIG. 1, so that only one single device under test (DUT) can be detected and tested at a time. To increase testing efficiency, some manufacturers may dispose a plurality of probing areas in one probe head for allowing each probing area to correspond to one single DUT, so that number of multiple DUTs can be detected at once. Such probing device can be referred to as a multi-DUT probing device, and the probing device similar to FIG. 1 can be referred to as a single DUT probing device.
Please refer to FIG. 2. FIG. 2 is a diagram illustrating another conventional multi-DUT probing device 20. The multi-DUT probing device 20 comprises a cage 21, a PCB 22, a space transformer 24, a reinforcing plate 25 and a probe head 26. The probe head 26 comprises a plurality of probing areas 27. As shown in FIG. 2, the reinforcing plate 25 is utilized to increase the overall mechanical strength of the multi-DUT probing device 20. Since the probe head 26 comprises a plurality of probing areas 27, where each probing area 27 corresponds to one DUT and comprises a plurality of probes 272, the multi-DUT probing device 20 can thus detect multiple number of DUTs at one time.
Although the multi-DUT probing device 20 can detect multiple number of DUTs at the same time, but due to the probe head 26 comprising a plurality of probing areas 27, the space transformer 24 is not interchangeable with the space transformer 14 of FIG. 1, as a result, redesign and remanufacturing are required. Consequently, the cost of the multi-DUT probing device is increased. Hence, allowing a multi-DUT probing device to continue to utilize the space transformer of a single-DUT probing device is an issue worth considering for those skilled in the art.
In Japan Patent Publication No. 2010266300, each space transformer is positioned using a reference base. After each space transformer is positioned the space transformer is then fixed onto a PCB. However, such positioning method is merely preliminary. When reflow soldering is performed later on, position of the space transformer may still be shifted away, thereby causing misalignment between probes of the probing areas and the pads on the space transformer.